Characteristics of concrete based on red waste ceramics and reinforced by steel fibre

Abstract

Red waste ceramics is gaining increasing popularity as raw material for aggregate production. Red waste ceramic aggregate (RWCA), due to its porous nature, is characterized by very high water absorptivity. It disables utilization of traditional concrete mix designing methods. The preparation of a workable RWCA mix is quite tricky. Replacing traditional coarse aggregates by RWCA significantly influences the homogeneity of mechanical properties of cast concrete (populations of results are characterized by significantly higher standard deviation) and mechanical properties themselves, preventing its wide production and application. In the research programme these limitations were addressed through utilizing engineered hooked steel fibre and the process of internal curing. Fibres were added to the mix by volume in amounts of 0.0%, 0.5%, 1.0% and 1.5%. Specimens for static tests were in a form of cubes (150 mm · 150 mm · 150 mm), cylinders (φ = 150 mm, h = 300 mm) and beams (b = 150 mm, h = 150 mm, l = 700 mm). Cubes and cylinders were used for strength tests according to EN 12390. Prismatic specimens were used for LOP test according to EN 14651:2005. Circular plates (φ = 1000 mm, h = 100 mm) were used for testing dynamic properties of the composites. The plates were mounted on a specially tailored laboratory stand and subjected to multiple free fall impacts. During the impact tests, deflection and propagation of cracks were followed. Created fibre reinforced RWCA concrete is characterized by compressive strength reaching 52 MPa and values of residual strengths enabling substitution of conventional reinforcement.